Red flags
- Onset after trauma, surgery or systemic infection
- Multiple areas involved or progressive symptoms
- Additional behavioural or memory changes, or dizziness/headaches
- Fever or other systemic upset
- Disturbances of autonomous nervous system or objective muscular weakness
- Patient is at high risk because of age, existing chronic conditions or lifestyle factors
Tingling sensations (paraesthesia) are common and are often temporary and harmless. Patients tend to present if there is a sudden onset of tingling over a large area, such as an entire limb or face.
They typically worry that they may be having a stroke. If a small area is affected or if symptoms recur over days or weeks, patients usually do not present for some time.
The experience of paraesthesia is subjective and can be difficult to describe. Patients may use terms such as 'trickling', 'pins and needles', 'like an electrical current' or descriptions such as pressure, tightness, heaviness or, also numbness. If the patient reports associated pain, then neuralgia would be readily considered.
Details about the onset, timeline and any variability of the symptoms are essential to help understand progression or regression, any patterns (or lack of) as well as the emotional and functional impact. It may be possible to identify if this sensation appears to affect a single nerve on one side of the body, or if it is symmetrically distributed on both sides of the body.
An occupational history and details of physical activities may reveal a musculoskeletal strain. A recent travel history is useful (long-haul flights or long car journeys, possible infection risks). The patient should also be asked about lifestyle factors that could indicate cancers, acute or chronic infections, metabolic diseases or alcoholism, for example.
Do not forget to check if the patient is taking medications, if these have been recently started or changed, and if they have attempted to self-treat the paraesthesia.
Possible causes
Possible causes of tingling include:
- Simple, temporary local mechanical pressure or repetitive strain (especially in elbows, shoulders, lower legs, cervical spine), or chronic nerve compression syndromes such as carpal tunnel syndrome. Other mechanical impacts, such as barotrauma or frostbite.
- Progressing arthritis, fibromyalgia, vertebral collapse or disc herniation, cervical rib, carcinomatosis, complex regional pain syndrome.
- Electrolyte disturbance (caused by hyperventilation, dehydration, hyper- or hypoglycaemia, kidney conditions, for example).
- Side-effects of medication such as benzodiazepines, SSRI withdrawal, or toxic effects from alcohol, chemotherapy or various types of metal poisoning.
- Genuine neurological conditions: brain or spinal compression processes, including abscesses, trauma, tumours or metastases, multiple sclerosis or motor neurone disease, polyneuropathy of diabetes.
- Sensory epilepsy or psychiatric conditions, such as somatoform disorders.
- Hypothyroidism, some autoimmune processes, or other metabolic conditions; malnutrition or vitamin deficiency (B12).
- Acute infections, or after-effects thereof, for example, herpes simplex, HIV, varicella zoster, Lyme disease, Guillain-Barré syndrome or Bell’s palsy.
- Vascular conditions, including acute limb ischaemia, thrombosis, chronic peripheral vascular disease, Raynaud's disease, TIA or migraines.
Short-term paraesthesia is most often caused by temporary pressure or other mechanical impact on nerves, but chronic paraesthesia is more likely to indicate a problem with the functioning of the anatomical neurons because of inflammation or poor circulation.
This may result directly from a problem of blood flow in the area (for example, constrictions or obstructions, impact of heat or cold, infection-induced or autoimmune conditions) or from metabolic disturbances, such as electrolytes or blood glucose.
Examination
Observe how the patient appears and behaves in the consultation. For example, do they seem confused or depressed?
A patient with large, multiple or unrelated areas affected would be of particular concern. Unless the affected area is clearly defined, it may not be possible to perform a complete neurological examination (sensation, sensory awareness, power, reflexes).
You should assess the movement of limbs and cervical spine. Any objective weakness or other neurological deficits would be significant until proven harmless.
Examine the skin for temperature differences or rashes, and check pulses as required. Note Lhermitte’s sign, in which a neuralgic spinal sensation is felt by the patient at neck flexion, suggesting MS. Tinel’s and Phalen’s tests can be done on the wrists to assess for carpal tunnel syndrome, albeit with fairly poor reliability.
Remote consultations are more common during the COVID-19 pandemic and although it can be difficult to establish all the above in a remote consultation, the patient may be able to be guided enough to check or demonstrate the essentials themselves. If this is not straightforward, then an examination in person is likely to be required.
Investigations
Consider baseline bloods to check for signs of inflammation, calcium and ESR, deficiencies in anaemia, vitamin B12, thiamin or ferritin, or metabolic dysfunction (liver, renal, glucose, thyroid).
Nerve conduction studies may be indicated and useful, depending on your local facilities.
In potential at-risk groups, such as smokers, consider a chest X-ray, even in the absence of other symptoms and normal chest auscultation.
Other investigations, including spinal MRI or CT head, may be indicated, but discuss with a radiologist or neurologist first, if possible.
Referral
Patients need to be investigated to identify the underlying diagnosis and referred promptly in the following situations.
- They have persistent or progressive symptoms
- They have sudden onset or unusual distribution of symptoms
- There are inconsistencies in history and findings
- They are at risk, for example, are elderly, have diabetes or are in generally poor health
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- Dr Tillmann Jacobi is a GP in York. This is an updated version of an article that was first published in May 2016.
